output: Make implementations inherit MetaOutput

Instead of the home baked "inheritance" system, using a gpointer and a
GDestroyNotify function to keep the what effectively is sub type
details, make MetaOutput an abstract derivable type, and make the
implementations inherit it.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1287

src/backends/meta-monitor-manager-dummy.c

@@ -53,10 +53,14 @@ struct _MetaMonitorManagerDummyClass
   MetaMonitorManagerClass parent_class;
 };
 
-typedef struct _MetaOutputDummy
+struct _MetaOutputDummy
 {
+  MetaOutput parent;
+
   float scale;
-} MetaOutputDummy;
+};
+
+G_DEFINE_TYPE (MetaOutputDummy, meta_output_dummy, META_TYPE_OUTPUT)
 
 G_DEFINE_TYPE (MetaMonitorManagerDummy, meta_monitor_manager_dummy, META_TYPE_MONITOR_MANAGER);
 
@@ -67,9 +71,6 @@ struct _MetaGpuDummy
 
 G_DEFINE_TYPE (MetaGpuDummy, meta_gpu_dummy, META_TYPE_GPU)
 
-static void
-meta_output_dummy_notify_destroy (MetaOutput *output);
-
 typedef struct _CrtcModeSpec
 {
   int width;
@@ -229,19 +230,13 @@ append_monitor (MetaMonitorManager *manager,
   output_info->possible_crtcs[0] = g_list_last (*crtcs)->data;
   output_info->n_possible_crtcs = 1;
 
-  output = g_object_new (META_TYPE_OUTPUT,
+  output = g_object_new (META_TYPE_OUTPUT_DUMMY,
                          "id", number,
                          "gpu", gpu,
                          "info", output_info,
                          NULL);
-
+  output_dummy = META_OUTPUT_DUMMY (output);
-  output_dummy = g_new0 (MetaOutputDummy, 1);
+  output_dummy->scale = scale;
-  *output_dummy = (MetaOutputDummy) {
-    .scale = scale
-  };
-  output->driver_private = output_dummy;
-  output->driver_notify =
-    (GDestroyNotify) meta_output_dummy_notify_destroy;
 
   *outputs = g_list_append (*outputs, output);
 }
@@ -307,11 +302,6 @@ append_tiled_monitor (MetaMonitorManager *manager,
       g_autoptr (MetaOutputInfo) output_info = NULL;
       GList *l;
 
-      output_dummy = g_new0 (MetaOutputDummy, 1);
-      *output_dummy = (MetaOutputDummy) {
-        .scale = scale
-      };
-
       /* Arbitrary ID unique for this output */
       number = g_list_length (*outputs) + 1;
 
@@ -359,25 +349,18 @@ append_tiled_monitor (MetaMonitorManager *manager,
         }
       output_info->n_possible_crtcs = n_tiles;
 
-      output = g_object_new (META_TYPE_OUTPUT,
+      output = g_object_new (META_TYPE_OUTPUT_DUMMY,
                              "id", number,
                              "gpu", gpu,
                              "info", output_info,
                              NULL);
-      output->driver_private = output_dummy;
+      output_dummy = META_OUTPUT_DUMMY (output);
-      output->driver_notify =
+      output_dummy->scale = scale;
-        (GDestroyNotify) meta_output_dummy_notify_destroy;
 
       *outputs = g_list_append (*outputs, output);
     }
 }
 
-static void
-meta_output_dummy_notify_destroy (MetaOutput *output)
-{
-  g_clear_pointer (&output->driver_private, g_free);
-}
-
 static void
 meta_monitor_manager_dummy_read_current (MetaMonitorManager *manager)
 {
@@ -652,7 +635,7 @@ meta_monitor_manager_dummy_calculate_monitor_mode_scale (MetaMonitorManager *man
   MetaOutputDummy *output_dummy;
 
   output = meta_monitor_get_main_output (monitor);
-  output_dummy = output->driver_private;
+  output_dummy = META_OUTPUT_DUMMY (output);
 
   return output_dummy->scale;
 }
@@ -799,3 +782,14 @@ meta_gpu_dummy_class_init (MetaGpuDummyClass *klass)
 
   gpu_class->read_current = meta_gpu_dummy_read_current;
 }
+
+static void
+meta_output_dummy_init (MetaOutputDummy *output_dummy)
+{
+  output_dummy->scale = 1;
+}
+
+static void
+meta_output_dummy_class_init (MetaOutputDummyClass *klass)
+{
+}

src/backends/meta-monitor-manager-dummy.h

@@ -25,6 +25,12 @@
 
 #include "backends/meta-gpu.h"
 #include "backends/meta-monitor-manager-private.h"
+#include "backends/meta-output.h"
+
+#define META_TYPE_OUTPUT_DUMMY (meta_output_dummy_get_type ())
+G_DECLARE_FINAL_TYPE (MetaOutputDummy, meta_output_dummy,
+                      META, OUTPUT_DUMMY,
+                      MetaOutput)
 
 #define META_TYPE_MONITOR_MANAGER_DUMMY (meta_monitor_manager_dummy_get_type ())
 G_DECLARE_FINAL_TYPE (MetaMonitorManagerDummy, meta_monitor_manager_dummy,

src/backends/meta-output.c

@@ -53,7 +53,7 @@ typedef struct _MetaOutputPrivate
   int backlight;
 } MetaOutputPrivate;
 
-G_DEFINE_TYPE_WITH_PRIVATE (MetaOutput, meta_output, G_TYPE_OBJECT)
+G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (MetaOutput, meta_output, G_TYPE_OBJECT)
 
 G_DEFINE_BOXED_TYPE (MetaOutputInfo, meta_output_info,
                      meta_output_info_ref,
@@ -308,9 +308,6 @@ meta_output_finalize (GObject *object)
   MetaOutput *output = META_OUTPUT (object);
   MetaOutputPrivate *priv = meta_output_get_instance_private (output);
 
-  if (output->driver_notify)
-    output->driver_notify (output);
-
   g_clear_pointer (&priv->info, meta_output_info_unref);
 
   G_OBJECT_CLASS (meta_output_parent_class)->finalize (object);

src/backends/meta-output.h

@@ -101,14 +101,6 @@ typedef struct _MetaOutputInfo
   MetaTileInfo tile_info;
 } MetaOutputInfo;
 
-struct _MetaOutput
-{
-  GObject parent;
-
-  gpointer driver_private;
-  GDestroyNotify driver_notify;
-};
-
 #define META_TYPE_OUTPUT_INFO (meta_output_info_get_type ())
 META_EXPORT_TEST
 GType meta_output_info_get_type (void);
@@ -129,7 +121,13 @@ void meta_output_info_parse_edid (MetaOutputInfo *output_info,
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (MetaOutputInfo, meta_output_info_unref)
 
 #define META_TYPE_OUTPUT (meta_output_get_type ())
-META_EXPORT_TEST G_DECLARE_FINAL_TYPE (MetaOutput, meta_output, META, OUTPUT, GObject)
+META_EXPORT_TEST
+G_DECLARE_DERIVABLE_TYPE (MetaOutput, meta_output, META, OUTPUT, GObject)
+
+struct _MetaOutputClass
+{
+  GObjectClass parent_class;
+};
 
 META_EXPORT_TEST
 uint64_t meta_output_get_id (MetaOutput *output);

src/backends/native/meta-crtc-kms.c

@@ -157,7 +157,7 @@ generate_crtc_connector_list (MetaGpu  *gpu,
       if (assigned_crtc == crtc)
         {
           MetaKmsConnector *kms_connector =
-            meta_output_kms_get_kms_connector (output);
+            meta_output_kms_get_kms_connector (META_OUTPUT_KMS (output));
 
           connectors = g_list_prepend (connectors, kms_connector);
         }

src/backends/native/meta-gpu-kms.c

@@ -238,7 +238,8 @@ meta_gpu_kms_set_power_save_mode (MetaGpuKms    *gpu_kms,
     {
       MetaOutput *output = l->data;
 
-      meta_output_kms_set_power_save_mode (output, state, kms_update);
+      meta_output_kms_set_power_save_mode (META_OUTPUT_KMS (output),
+                                           state, kms_update);
     }
 }
 
@@ -367,7 +368,8 @@ find_output_by_connector_id (GList    *outputs,
     {
       MetaOutput *output = l->data;
 
-      if (meta_output_kms_get_connector_id (output) == connector_id)
+      if (meta_output_kms_get_connector_id (META_OUTPUT_KMS (output)) ==
+          connector_id)
         return output;
     }
 
@@ -391,7 +393,8 @@ setup_output_clones (MetaGpu *gpu)
           if (other_output == output)
             continue;
 
-          if (meta_output_kms_can_clone (output, other_output))
+          if (meta_output_kms_can_clone (META_OUTPUT_KMS (output),
+                                         META_OUTPUT_KMS (other_output)))
             meta_output_add_possible_clone (output, other_output);
         }
     }
@@ -515,7 +518,7 @@ init_outputs (MetaGpuKms *gpu_kms)
     {
       MetaKmsConnector *kms_connector = l->data;
       const MetaKmsConnectorState *connector_state;
-      MetaOutput *output;
+      MetaOutputKms *output_kms;
       MetaOutput *old_output;
       GError *error = NULL;
 
@@ -526,18 +529,18 @@ init_outputs (MetaGpuKms *gpu_kms)
       old_output =
         find_output_by_connector_id (old_outputs,
                                      meta_kms_connector_get_id (kms_connector));
-      output = meta_create_kms_output (gpu_kms,
+      output_kms = meta_output_kms_new (gpu_kms,
                                         kms_connector,
                                         old_output,
                                         &error);
-      if (!output)
+      if (!output_kms)
         {
           g_warning ("Failed to create KMS output: %s", error->message);
           g_error_free (error);
         }
       else
         {
-          outputs = g_list_prepend (outputs, output);
+          outputs = g_list_prepend (outputs, output_kms);
         }
     }
 

src/backends/native/meta-monitor-manager-kms.c

@@ -95,7 +95,7 @@ static GBytes *
 meta_monitor_manager_kms_read_edid (MetaMonitorManager *manager,
                                     MetaOutput         *output)
 {
-  return meta_output_kms_read_edid (output);
+  return meta_output_kms_read_edid (META_OUTPUT_KMS (output));
 }
 
 static void

src/backends/native/meta-output-kms.c

@@ -44,19 +44,19 @@ typedef struct _MetaOutputKms
   MetaKmsConnector *kms_connector;
 } MetaOutputKms;
 
-MetaKmsConnector *
+G_DEFINE_TYPE (MetaOutputKms, meta_output_kms, META_TYPE_OUTPUT)
-meta_output_kms_get_kms_connector (MetaOutput *output)
-{
-  MetaOutputKms *output_kms = output->driver_private;
 
+MetaKmsConnector *
+meta_output_kms_get_kms_connector (MetaOutputKms *output_kms)
+{
   return output_kms->kms_connector;
 }
 
 void
-meta_output_kms_set_underscan (MetaOutput    *output,
+meta_output_kms_set_underscan (MetaOutputKms *output_kms,
                                MetaKmsUpdate *kms_update)
 {
-  MetaOutputKms *output_kms = output->driver_private;
+  MetaOutput *output = META_OUTPUT (output_kms);
   const MetaOutputInfo *output_info = meta_output_get_info (output);
 
   if (!output_info->supports_underscanning)
@@ -93,20 +93,16 @@ meta_output_kms_set_underscan (MetaOutput    *output,
 }
 
 uint32_t
-meta_output_kms_get_connector_id (MetaOutput *output)
+meta_output_kms_get_connector_id (MetaOutputKms *output_kms)
 {
-  MetaOutputKms *output_kms = output->driver_private;
-
   return meta_kms_connector_get_id (output_kms->kms_connector);
 }
 
 void
-meta_output_kms_set_power_save_mode (MetaOutput    *output,
+meta_output_kms_set_power_save_mode (MetaOutputKms *output_kms,
                                      uint64_t       dpms_state,
                                      MetaKmsUpdate *kms_update)
 {
-  MetaOutputKms *output_kms = output->driver_private;
-
   g_debug ("Setting DPMS state of connector %s to %" G_GUINT64_FORMAT,
            meta_kms_connector_get_name (output_kms->kms_connector),
            dpms_state);
@@ -117,20 +113,16 @@ meta_output_kms_set_power_save_mode (MetaOutput    *output,
 }
 
 gboolean
-meta_output_kms_can_clone (MetaOutput *output,
+meta_output_kms_can_clone (MetaOutputKms *output_kms,
-                           MetaOutput *other_output)
+                           MetaOutputKms *other_output_kms)
 {
-  MetaOutputKms *output_kms = output->driver_private;
-  MetaOutputKms *other_output_kms = other_output->driver_private;
-
   return meta_kms_connector_can_clone (output_kms->kms_connector,
                                        other_output_kms->kms_connector);
 }
 
 GBytes *
-meta_output_kms_read_edid (MetaOutput *output)
+meta_output_kms_read_edid (MetaOutputKms *output_kms)
 {
-  MetaOutputKms *output_kms = output->driver_private;
   const MetaKmsConnectorState *connector_state;
   GBytes *edid_data;
 
@@ -143,16 +135,6 @@ meta_output_kms_read_edid (MetaOutput *output)
   return g_bytes_new_from_bytes (edid_data, 0, g_bytes_get_size (edid_data));
 }
 
-static void
-meta_output_destroy_notify (MetaOutput *output)
-{
-  MetaOutputKms *output_kms;
-
-  output_kms = output->driver_private;
-
-  g_slice_free (MetaOutputKms, output_kms);
-}
-
 static void
 add_common_modes (MetaOutputInfo *output_info,
                   MetaGpuKms     *gpu_kms)
@@ -287,8 +269,8 @@ init_output_modes (MetaOutputInfo    *output_info,
   return TRUE;
 }
 
-MetaOutput *
+MetaOutputKms *
-meta_create_kms_output (MetaGpuKms        *gpu_kms,
+meta_output_kms_new (MetaGpuKms        *gpu_kms,
                      MetaKmsConnector  *kms_connector,
                      MetaOutput        *old_output,
                      GError           **error)
@@ -355,16 +337,12 @@ meta_create_kms_output (MetaGpuKms        *gpu_kms,
 
   output_info->tile_info = connector_state->tile_info;
 
-  output = g_object_new (META_TYPE_OUTPUT,
+  output = g_object_new (META_TYPE_OUTPUT_KMS,
                          "id", ((uint64_t) gpu_id << 32) | connector_id,
                          "gpu", gpu,
                          "info", output_info,
                          NULL);
-
+  output_kms = META_OUTPUT_KMS (output);
-  output_kms = g_slice_new0 (MetaOutputKms);
-  output->driver_private = output_kms;
-  output->driver_notify = (GDestroyNotify) meta_output_destroy_notify;
-
   output_kms->kms_connector = kms_connector;
 
   if (connector_state->current_crtc_id)
@@ -401,5 +379,15 @@ meta_create_kms_output (MetaGpuKms        *gpu_kms,
       meta_output_unassign_crtc (output);
     }
 
-  return output;
+  return output_kms;
+}
+
+static void
+meta_output_kms_init (MetaOutputKms *output_kms)
+{
+}
+
+static void
+meta_output_kms_class_init (MetaOutputKmsClass *klass)
+{
 }

src/backends/native/meta-output-kms.h

@@ -27,23 +27,28 @@
 #include "backends/native/meta-gpu-kms.h"
 #include "backends/native/meta-kms-types.h"
 
-void meta_output_kms_set_power_save_mode (MetaOutput    *output,
+#define META_TYPE_OUTPUT_KMS (meta_output_kms_get_type ())
+G_DECLARE_FINAL_TYPE (MetaOutputKms, meta_output_kms,
+                      META, OUTPUT_KMS,
+                      MetaOutput)
+
+void meta_output_kms_set_power_save_mode (MetaOutputKms *output_kms,
                                           uint64_t       dpms_state,
                                           MetaKmsUpdate *kms_update);
 
-void meta_output_kms_set_underscan (MetaOutput    *output,
+void meta_output_kms_set_underscan (MetaOutputKms *output_kms,
                                     MetaKmsUpdate *kms_update);
 
-gboolean meta_output_kms_can_clone (MetaOutput *output,
+gboolean meta_output_kms_can_clone (MetaOutputKms *output_kms,
-                                    MetaOutput *other_output);
+                                    MetaOutputKms *other_output_kms);
 
-MetaKmsConnector * meta_output_kms_get_kms_connector (MetaOutput *output);
+MetaKmsConnector * meta_output_kms_get_kms_connector (MetaOutputKms *output_kms);
 
-uint32_t meta_output_kms_get_connector_id (MetaOutput *output);
+uint32_t meta_output_kms_get_connector_id (MetaOutputKms *output_kms);
 
-GBytes * meta_output_kms_read_edid (MetaOutput *output);
+GBytes * meta_output_kms_read_edid (MetaOutputKms *output_kms);
 
-MetaOutput * meta_create_kms_output (MetaGpuKms        *gpu_kms,
+MetaOutputKms * meta_output_kms_new (MetaGpuKms        *gpu_kms,
                                      MetaKmsConnector  *kms_connector,
                                      MetaOutput        *old_output,
                                      GError           **error);

src/backends/native/meta-renderer-native.c

@@ -1436,7 +1436,8 @@ meta_onscreen_native_set_crtc_mode (CoglOnscreen              *onscreen,
     }
 
   meta_crtc_kms_set_mode (onscreen_native->crtc, kms_update);
-  meta_output_kms_set_underscan (onscreen_native->output, kms_update);
+  meta_output_kms_set_underscan (META_OUTPUT_KMS (onscreen_native->output),
+                                 kms_update);
 }
 
 static void

src/backends/x11/meta-gpu-xrandr.c

@@ -191,14 +191,14 @@ meta_gpu_xrandr_read_current (MetaGpu  *gpu,
 
       if (xrandr_output->connection != RR_Disconnected)
         {
-          MetaOutput *output;
+          MetaOutputXrandr *output_xrandr;
 
-          output = meta_create_xrandr_output (gpu_xrandr,
+          output_xrandr = meta_output_xrandr_new (gpu_xrandr,
                                                   xrandr_output,
                                                   output_id,
                                                   primary_output);
-          if (output)
+          if (output_xrandr)
-            outputs = g_list_prepend (outputs, output);
+            outputs = g_list_prepend (outputs, output_xrandr);
         }
 
       XRRFreeOutputInfo (xrandr_output);

src/backends/x11/meta-monitor-manager-xrandr.c

@@ -540,7 +540,7 @@ apply_crtc_assignments (MetaMonitorManager    *manager,
       MetaOutputAssignment *output_assignment = outputs[i];
       MetaOutput *output = output_assignment->output;
 
-      meta_output_xrandr_apply_mode (output);
+      meta_output_xrandr_apply_mode (META_OUTPUT_XRANDR (output));
     }
 
   g_list_foreach (to_configure_outputs,
@@ -643,7 +643,7 @@ meta_monitor_manager_xrandr_change_backlight (MetaMonitorManager *manager,
 					      MetaOutput         *output,
 					      gint                value)
 {
-  meta_output_xrandr_change_backlight (output, value);
+  meta_output_xrandr_change_backlight (META_OUTPUT_XRANDR (output), value);
 }
 
 static void

src/backends/x11/meta-output-xrandr.c

@@ -46,6 +46,13 @@
 #include "backends/x11/meta-monitor-manager-xrandr.h"
 #include "meta/util.h"
 
+struct _MetaOutputXrandr
+{
+  MetaOutput parent;
+};
+
+G_DEFINE_TYPE (MetaOutputXrandr, meta_output_xrandr, META_TYPE_OUTPUT)
+
 static Display *
 xdisplay_from_gpu (MetaGpu *gpu)
 {
@@ -133,8 +140,9 @@ output_set_underscanning_xrandr (MetaOutput *output,
 }
 
 void
-meta_output_xrandr_apply_mode (MetaOutput *output)
+meta_output_xrandr_apply_mode (MetaOutputXrandr *output_xrandr)
 {
+  MetaOutput *output = META_OUTPUT (output_xrandr);
   Display *xdisplay = xdisplay_from_output (output);
 
   if (meta_output_is_primary (output))
@@ -163,9 +171,10 @@ normalize_backlight (MetaOutput *output,
 }
 
 void
-meta_output_xrandr_change_backlight (MetaOutput *output,
+meta_output_xrandr_change_backlight (MetaOutputXrandr *output_xrandr,
                                      int               value)
 {
+  MetaOutput *output = META_OUTPUT (output_xrandr);
   const MetaOutputInfo *output_info = meta_output_get_info (output);
   Display *xdisplay = xdisplay_from_output (output);
   Atom atom;
@@ -786,8 +795,8 @@ find_assigned_crtc (MetaGpu       *gpu,
   return NULL;
 }
 
-MetaOutput *
+MetaOutputXrandr *
-meta_create_xrandr_output (MetaGpuXrandr *gpu_xrandr,
+meta_output_xrandr_new (MetaGpuXrandr *gpu_xrandr,
                         XRROutputInfo *xrandr_output,
                         RROutput       output_id,
                         RROutput       primary_output)
@@ -859,7 +868,7 @@ meta_create_xrandr_output (MetaGpuXrandr *gpu_xrandr,
     output_get_supports_underscanning_xrandr (xdisplay, output_id);
   output_info_init_backlight_limits_xrandr (output_info, xdisplay, output_id);
 
-  output = g_object_new (META_TYPE_OUTPUT,
+  output = g_object_new (META_TYPE_OUTPUT_XRANDR,
                          "id", output_id,
                          "gpu", gpu_xrandr,
                          "info", output_info,
@@ -892,6 +901,16 @@ meta_create_xrandr_output (MetaGpuXrandr *gpu_xrandr,
     }
   else
     {
-      return output;
+      return META_OUTPUT_XRANDR (output);
     }
 }
+
+static void
+meta_output_xrandr_init (MetaOutputXrandr *output_xrandr)
+{
+}
+
+static void
+meta_output_xrandr_class_init (MetaOutputXrandrClass *klass)
+{
+}

src/backends/x11/meta-output-xrandr.h

@@ -28,14 +28,19 @@
 #include "backends/x11/meta-gpu-xrandr.h"
 #include "backends/x11/meta-monitor-manager-xrandr.h"
 
-void meta_output_xrandr_apply_mode (MetaOutput *output);
+#define META_TYPE_OUTPUT_XRANDR (meta_output_xrandr_get_type ())
+G_DECLARE_FINAL_TYPE (MetaOutputXrandr, meta_output_xrandr,
+                      META, OUTPUT_XRANDR,
+                      MetaOutput)
 
-void meta_output_xrandr_change_backlight (MetaOutput *output,
+void meta_output_xrandr_apply_mode (MetaOutputXrandr *output_xrandr);
+
+void meta_output_xrandr_change_backlight (MetaOutputXrandr *output_xrandr,
                                           int         value);
 
-GBytes * meta_output_xrandr_read_edid (MetaOutput *output);
+GBytes * meta_output_xrandr_read_edid (MetaOutput *output_xrandr);
 
-MetaOutput * meta_create_xrandr_output (MetaGpuXrandr *gpu_xrandr,
+MetaOutputXrandr * meta_output_xrandr_new (MetaGpuXrandr *gpu_xrandr,
                                            XRROutputInfo *xrandr_output,
                                            RROutput       output_id,
                                            RROutput       primary_output);

src/tests/headless-start-test.c

@@ -163,7 +163,7 @@ meta_test_headless_monitor_connect (void)
   output_info->possible_crtcs = possible_crtcs;
   output_info->connector_type = META_CONNECTOR_TYPE_DisplayPort;
 
-  output = g_object_new (META_TYPE_OUTPUT,
+  output = g_object_new (META_TYPE_OUTPUT_TEST,
                          "id", 1,
                          "gpu", gpu,
                          "info", output_info,

src/tests/meta-monitor-manager-test.c

@@ -28,6 +28,8 @@
 #include "backends/meta-output.h"
 #include "tests/meta-backend-test.h"
 
+G_DEFINE_TYPE (MetaOutputTest, meta_output_test, META_TYPE_OUTPUT)
+
 struct _MetaMonitorManagerTest
 {
   MetaMonitorManager parent;
@@ -296,7 +298,7 @@ meta_monitor_manager_test_calculate_monitor_mode_scale (MetaMonitorManager *mana
   MetaOutputTest *output_test;
 
   output = meta_monitor_get_main_output (monitor);
-  output_test = output->driver_private;
+  output_test = META_OUTPUT_TEST (output);
 
   if (output_test)
     return output_test->scale;
@@ -423,3 +425,14 @@ meta_monitor_manager_test_class_init (MetaMonitorManagerTestClass *klass)
   manager_class->get_max_screen_size = meta_monitor_manager_test_get_max_screen_size;
   manager_class->get_default_layout_mode = meta_monitor_manager_test_get_default_layout_mode;
 }
+
+static void
+meta_output_test_init (MetaOutputTest *output_test)
+{
+  output_test->scale = 1;
+}
+
+static void
+meta_output_test_class_init (MetaOutputTestClass *klass)
+{
+}

src/tests/meta-monitor-manager-test.h

@@ -21,6 +21,7 @@
 #define META_MONITOR_MANAGER_TEST_H
 
 #include "backends/meta-monitor-manager-private.h"
+#include "backends/meta-output.h"
 
 typedef struct _MetaMonitorTestSetup
 {
@@ -29,13 +30,20 @@ typedef struct _MetaMonitorTestSetup
   GList *crtcs;
 } MetaMonitorTestSetup;
 
-typedef struct _MetaOutputTest
+struct _MetaOutputTest
 {
+  MetaOutput parent;
+
   float scale;
-} MetaOutputTest;
+};
 
 typedef MetaMonitorTestSetup * (* CreateTestSetupFunc) (void);
 
+#define META_TYPE_OUTPUT_TEST (meta_output_test_get_type ())
+G_DECLARE_FINAL_TYPE (MetaOutputTest, meta_output_test,
+                      META, OUTPUT_TEST,
+                      MetaOutput)
+
 #define META_TYPE_MONITOR_MANAGER_TEST (meta_monitor_manager_test_get_type ())
 G_DECLARE_FINAL_TYPE (MetaMonitorManagerTest, meta_monitor_manager_test,
                       META, MONITOR_MANAGER_TEST, MetaMonitorManager)

src/tests/monitor-test-utils.c

@@ -529,12 +529,6 @@ check_monitor_configuration (MonitorTestCaseExpect *expect)
     }
 }
 
-static void
-meta_output_test_destroy_notify (MetaOutput *output)
-{
-  g_clear_pointer (&output->driver_private, g_free);
-}
-
 MetaMonitorTestSetup *
 create_monitor_test_setup (MonitorTestCaseSetup *setup,
                            MonitorTestFlag       flags)
@@ -627,16 +621,10 @@ create_monitor_test_setup (MonitorTestCaseSetup *setup,
                                                possible_crtc_index);
         }
 
-      output_test = g_new0 (MetaOutputTest, 1);
-
       scale = setup->outputs[i].scale;
       if (scale < 1)
         scale = 1;
 
-      *output_test = (MetaOutputTest) {
-        .scale = scale
-      };
-
       is_laptop_panel = setup->outputs[i].is_laptop_panel;
 
       serial = setup->outputs[i].serial;
@@ -679,12 +667,15 @@ create_monitor_test_setup (MonitorTestCaseSetup *setup,
       output_info->panel_orientation_transform =
         setup->outputs[i].panel_orientation_transform;
 
-      output = g_object_new (META_TYPE_OUTPUT,
+      output = g_object_new (META_TYPE_OUTPUT_TEST,
                              "id", i,
                              "gpu", test_get_gpu (),
                              "info", output_info,
                              NULL);
 
+      output_test = META_OUTPUT_TEST (output);
+      output_test->scale = scale;
+
       if (crtc)
         {
           MetaOutputAssignment output_assignment;
@@ -695,9 +686,6 @@ create_monitor_test_setup (MonitorTestCaseSetup *setup,
           meta_output_assign_crtc (output, crtc, &output_assignment);
         }
 
-      output->driver_private = output_test;
-      output->driver_notify = (GDestroyNotify) meta_output_test_destroy_notify;
-
       test_setup->outputs = g_list_append (test_setup->outputs, output);
     }